The present invention relates generally to a gap-sealing structure, and more particularly to such structure which is especially suitable for sealing the gaps between the panels of roofs and the like.
Building roofs must be tightly sealed against the entry of moisture, a problem which presents particular difficulties where flat roofs are involved. Unlike inclined roofs where a roof covering can be overlapped so that water which runs down over the roof cannot enter into gaps between adjacent roof covering elements, this is not possible in flat roofs. Heretofore, flat roofs were usually sealed by placing upon them several layers of roofing felt which are adhered together. Usually, a layer of gravel is then placed on top to protect the roofing felt against deterioration as much as possible.
Another approach that has become known in the prior art is to cover the entire roofing surface with watertight foils, for instance of synthetic plastic material. In this case also the roof is usually provided with a final layer of gravel in order to protect the foil against the damaging influences of the ambient atmosphere, and also to prevent the foil from being lifted off in the event of high winds.
Both of these prior-art approaches are highly successful, and as a general rule will provide the desired sealing of the roof. They do, however, have certain disadvantages. In particular, roofs which are so covered cannot support any significant weight and cannot, therefore, be used as patios, terraces or the like. This can cause a substantial loss of potentially available valuable space. Another difficulty is the fact that these roofs are relatively expensive in terms of the material costs involved, as well as the time and labor expenses for installing them. Another disadvantage results from the inclusion in the roofing substances of organic materials which are subject to destruction under atmospheric influences, heat, moisture, and radiation, and which also support combustion.
To overcome the aforementioned disadvantages, roofs in general, and flat roofs in particular, should ideally be made of rigid panels that are capable of supporting weight and are composed of inorganic materials, such as asbestos cement, concrete, reinforced glass, metal or the like. However, as has already been pointed out earlier, attempts at using such panels without overlying layers of roofing felt or foils have been unsuccessful because the gaps between adjacent ones of the panels have heretofore never been satisfactorily sealed against the entry of moisture. It was attempted to fill the gaps with sealing materials, for instance synthetic plastic material. However, the volumetric content of these gaps is relatively small, since the panels are not very thick and must not be installed too far apart. This means that it is not possible to introduce a substantial amount of sealing material into the gaps and the amount that can be so introduced is not sufficient to withstand the stresses which act upon it when the roof panels are subject to thermal expansion and contraction. It was observed that ever after a brief period of time following the installation, cracks developed in the sealing material, permitting the entry of water into the gap and into the underlying structure beneath the roof. Moreover, because the introduction of the sealing material into the gaps must take place in the open, the presence of moisture during the introduction could often not be precluded, and this led to improper bonding of the sealing material with the panels. For this reason, the inherently advantageous use of roof panels without any necessity for overlying layers of roofing felt or foils, have not found any introduction in actual practice until now.